1. Object of the Invention
This invention relates to a process for producing methyl formate which comprises dehydrogenating methanol in vapor phase.
2. Description of the Prior Art
A process for producing methyl formate which comprises dehydrogenating methanol in the presence of certain catalysts is known. For example, a copper catalyst is disclosed in French Pat. No. 673,337, a catalyst obtained by reducing oxides of copper, nickel, chrome and iron (U.S. Pat. No. 1,400,195), and a catalyst obtained by treating copper-aluminum alloy with an aqueous alkaline solution (U.S. Pat. No. 2,504,497), are known as such catalysts. Also, Horton U.S. Pat. No. 2,522,676 discloses a process for producing esters by reacting primary alcohols with sulphur in the absence of any catalyst. In the explanation on the prior art of Horton, Horton states that a mixture of copper and rare metals such as cerium, zirconium or uranium is known as a catalyst for dehydrogenating primary alcohols to form esters. However, these patents do not disclose the yield of methyl formate obtained. We have found that when methanol is dehydrogenated in the presence of copper, methyl formate can not be obtained with excellent selectivity.
We have carried out research for obtaining methyl formate from methanol with high selectivity. As a result, we have found that when methanol is dehydrogenated in vapor phase in the presence of a catalyst comprising copper and at least one element selected from the group consisting of the elements of Group IIIA of the periodic table, the elements of Group IVA of the periodic table, the rare earth elements and the actinide elements as an effective component, methyl formate can be obtained in a high selectivity (refer to U.S. Ser. No. 786,408, filed Apr. 11, 1977, assigned to the assignee of this application). It was found that of these catalysts, a catalyst comprising copper and zirconium gives an excellent selectivity to methyl formate as well as an increased yield of methyl formate. But the activity of the catalyst tended to decrease in a short period.